Marriage is called to be not only an object but a subject of the new evangelization.
With these words, Pope Benedict XVI opened the thirteenth Ordinary General Assembly of the Synod of Bishops on the theme The New Evangelization for the Transmission of the Christian Faith. He explained that:
Matrimony is a Gospel in itself, a Good News for the world of today, especially the dechristianized world. The union of a man and a woman, their becoming “one flesh” in charity, in fruitful and indissoluble love, is a sign that speaks of God with a force and an eloquence which in our days has become greater because unfortunately, for various reasons, marriage, in precisely the oldest regions evangelized, is going through a profound crisis. And it is not by chance. Marriage is linked to faith, but not in a general way. Marriage, as a union of faithful and indissoluble love, is based upon the grace that comes from the triune God, who in Christ loved us with a faithful love, even to the Cross. Today we ought to grasp the full truth of this statement, in contrast to the painful reality of many marriages which, unhappily, end badly. (emphasis added)
In the Pastoral Constitution on the Church in the Modern World, Vatican II stated it this way:
Finally, let the spouses themselves, made to the image of the living God and enjoying the authentic dignity of persons, be joined to one another in equal affection, harmony of mind and the work of mutual sanctification. Thus, following Christ who is the principle of life, by the sacrifices and joys of their vocation and through their faithful love, married people can become witnesses of the mystery of love which the Lord revealed to the world by His dying and His rising up to life again. (emphasis added)
In Evangelii Nuntiandi, Pope Paul VI highlighted the importance of marriage and family in evangelization:
One cannot fail to stress the evangelizing action of the family in the evangelizing apostolate of the laity…In a family…all the members evangelize and are evangelized. The parents not only communicate the Gospel to their children, but from their children they can themselves receive the same Gospel as deeply lived by them. And such a family becomes the evangelizer of many other families, and of the neighborhood of which it forms part.  (emphasis added)
In concluding his address to the Synod, Pope Benedict XVI said “there is a clear link between the crisis in faith and the crisis in marriage.” Three years earlier, he characterized the crisis of faith as follows:
In our days, when in vast areas of the world the faith is in danger of dying out like a flame which no longer has fuel, the overriding priority is to make God present in this world and to show men and women the way to God. Not just any god, but the God who spoke on Sinai; to that God whose face we recognize in a love which presses “to the end” (cf. Jn 13:1) – in Jesus Christ, crucified and risen. The real problem at this moment of our history is that God is disappearing from the human horizon, and, with the dimming of the light which comes from God, humanity is losing its bearings, with increasingly evident destructive effects. (emphasis added)
Likewise, marriage is in crisis today. The traditional family – one man, one woman, married for life – is no longer the norm. “The American divorce rate today is about twice that of 1960. For the average couple marrying for the first time in recent years, the lifetime probability of divorce or separation now falls between 40 and 50 percent.” In addition, “Between 1960 and 2011, the number of unmarried couples in America increased more than seventeen-fold.” Cohabitating couples that eventually marry have a shocking divorce rate of 80 percent.
If we are going to change our culture, evangelization efforts need to start with the family. We exhort you to show married — and engaged — couples the way to God. By evangelizing husbands and wives, we make them the object of the new evangelization. They in turn become evangelizers, or the subjects of the new evangelization.
 Benedict XVI, Homily for Holy Mass for the Opening of the Synod of Bishops, October 7, 2012, http://w2.vatican.va/content/benedict-xvi/en/homilies/2012/documents/hf_ben-xvi_hom_20121007_apertura-sinodo.html (accessed November 16, 2016).
 Paul VI, Vatican II Council Pastoral Constitution on the Church in the Modern World, §52, December 7, 1965, http://www.vatican.va/archive/hist_councils/ii_vatican_council/documents/vat-ii_cons_19651207_gaudium-et-spes_en.html (accessed November 27, 2016).
 Paul VI, Apostolic Exhortation Evangelii Nuntiandi, §71, December 8, 1975; http://w2.vatican.va/content/paul-vi/en/apost_exhortations/documents/hf_p-vi_exh_19751208_evangelii-nuntiandi.html (accessed November 27, 2016).
 Benedict XVI, Letter of his Holiness Pope Benedict XVI to the Bishops of the Catholic Church Concerning the Remission of the Excommunication of the Four Bishops Consecrated by Archbishop Lefebvre, March 10, 2009, https://w2.vatican.va/content/benedict-xvi/en/letters/2009/documents/hf_ben-xvi_let_20090310_remissione-scomunica.html (accessed November 26, 2016).
 W. Bradford Wilcox, Ed., The State of Our Unions: Marriage in American 2012, http://www.stateofourunions.org/2012/social_indicators.php#divorce (accessed November 27, 2016).
 Ibid., http://www.stateofourunions.org/2012/social_indicators.php#cohabitation (accessed November 27, 2016).
 Love Undefiled, http://loveundefiled.blogspot.com/2009/06/study-shows-divorce-rate-of.html (accessed November 27, 2016).
 Benedict XVI, Letter of his Holiness Pope Benedict XVI to the Bishops of the Catholic Church Concerning the Remission of the Excommunication of the Four Bishops Consecrated by Archbishop Lefebvre.